Curing epoxy resin with an amino-poly-imidazoline



llnited States Patent 6 3,002,941 CURING EPOXY RESIN WITH AN AMINO-POLY-IMIDAZOLINE Lowell Peterson, Anoka, Minn., assignor to General Mills,

c., a corporation of Delaware No Drawing. Filed May 17, 1957, Ser. No. 659,759 2 Claims. (Cl. 260-18) This invention relates to new and useful reaction products of polymeric fat acids and polyamines and their method of preparation.

Polymeric fat acids and various polyamines have been employed in the preparation of polyamides. These polyamides vary in physical properties from hard solids to semidiquids depending principally upon the type and amount of polyamine employed in their preparation.

Recent discoveries relating to the utilization of the semi-liquid polyamides containing reactive amino groups as co-reactants with various other polymeric materials greatly increased the demand for this type of product. For instance, when reacted with epoxy resins and/or various phenolic resins, the resulting products have many unique properties, especially in respect to impact resistance and flexural strengtht An object of this inventionis to teach a reaction product of polymeric fat acids and polyamines which- The polymeric fat acids employed in preparing the new reaction products are those resulting from the polymerization of drying or semi-drying oils, or their free acids or the simple aliphatic alcohol ester of these acids, particularly sources rich in linoleic acid. Suitable drying or semi-drying oils include soybean, linseed, tung, perilla, cottonseed, corn, sunflower, safliower, and dehydrated castor. Suitable fatty acids may also be ob tained from tall oil, soapstock, and other similar material. In the polymerization process for the preparation of the polymeric fat acids the fatty acids with sufiicient double bond functionality combine for the most part, probably by a Diels-Alder mechanism, to provide a mixture of dibasic and higher polymeric fat acids. These acids are often referred to as dimers, trimers, etc. In place of this method of polymerization, any other method of polymerization may be employed whether the resultant polymer possesses residual unsaturation or not. For example, monoor polyene fat acids may be polymeriz'ed in the presence of ditertiaryhutyl peroxide to yield polymeric fat acids useful in the present invention. The term polymeric fat acids as used herein is intended to include any individual polymerized fat acid as well as a polymerized mixture of acids, the latter usually containing a predominant portion of dimer acids, a small quantity'of trimer and higher polymeric fat acids and has an appreciably lower viscosity than heretofore available reaction products. -A primary advantage to these products is that they materially reduce the viscosity of.

compositions containing other more viscous materials. For instance, when employed with epoxy resins bothersome diluents may be eliminated, epoxy resins of higher viscosity and molecular weight may be utilized in 100% solids protective coating compositions and their useful 7 applications are both aided and extended.

Another unexpected advantage to the reaction prod-o,

nets of this invention is that they are lighter in color than the presently available reaction products of polymeric fat acids and polyamines. V r

A still further advantage to the products of this invention isin their use as ace-reactant with epoxy resins. When employed in this fashion the resulting product has a higher heat distortion temperature thanthe analogous product prepared from amino-polya'mides derived from polymeric fat acids and polyamines.

Other objects and advantages to this invention will become apparent upon reading the subsequent specification.

The new and useful products of this invention may be prepared by reacting polymeric fat acids and polyamines at temperatures within the range of 285 to 315 C. These products are characterized by the fact that they contain a large percentage of imidazoline groups as compared to amide linkages. The products may be defined more specifically by the fact that they contain at least 2 imidazoline groups for every amide linkage. It will also be appreciated that the imidazoline nucleus,

ZN-C HI --C \N HI itself contains a reactive hydrogen or amine tail, such as -CH CH NH at position A.

some residual monomer.

While a variety of polymeric fat acids may be used, the most readily available source of such acids is through the polymerization of linoleic acid or linolenic acid rich materials. It should be appreciated that since linoleic acid occurs in nature as a complex mixture in every instance, it is available in various degrees of purity ranging from relatively expensive pure linoleic acid that has been laboriously purified to crude sources such as tall oil and soapstock which contain substances other than fatty acids. In actual practice linoleic acid rich mixtures of fatty acids are used to prepare the polymeric fat acids. One method of obtaining the linoleic acid rich fatty acids is by separating a major portion of the oleic and saturated fatty acids from any convenient and economical source of fatty acids having a high iodine value. In addition, polymeric fat acids are readily available commercial products. One such product is Empol 1022 as sold by Emery Industries, Inc.

'It has been postulated that the structural formula of the dimer acid from linoleic acid is as follows:

The trimer is then formed from the dimer by a Diels- Alder reaction with linoleic or linolenic acid at either of the double bonds shown in the above formula.

Polyamines useful in the practice of this invention may be illustrated by the general formula where R is hydrogen or a lower alkyl radical containing less than 5 carbon atoms and n is an integer less than 6. Illustrative polyamines are ethylenediamine (EDA),

- 3 diethylenetriamine (DETA) triethylenetetramine (TETA), tetraethylenepentamine (TEPA), di-l,2-propanetriamine and the like.

The ratio of polymeric fat acids and polyamines which may be employed varies from 0.5 to 1.5 moles of polyamine per equivalent of acid.

This invention may be illustrated further by reference to the following examples in which all parts are expressed as parts by weight and all percentages are expressed as percent by weight, unless specified otherwise.

EXAMPLE I 1982 grams of polymeric fat acids containing a preponderance of di-linoleic acid and having a saponifica tion equivalent of 284.5 were reacted with 1018 grams of triethylene tetramine as follows:

(1) The reactants were heated and stirred continuously in a five liter flask equipped with thermometer and distillation head.

(2) At 160 C. water was evolved, and the reaction mixture was then raised to 300 C. over a 4 hour period.

(3) Reaction at 300 C. was continued for 2 hours at the end of which time a total of 246 gm. of distillate had been collected.

The resulting product had a Brookfield viscosity of 128 poises as measured on a #5 spindle at r.p.m. and 24 C. Upon being reacted with an unmodified epoxy resin prepared by reacting Bis-phenol A and epichlorohydrin and having an epoxy equivalency of about 200 in the ratio of 30 parts to 70 parts epoxy resin at 150 C. for 2 hours. The resulting casting had a heat distortion temperature of 96 C., a flexural modulus of 3.3)(10 Table 1 Reaction Brookfield Sample No. Polyamine Temper- Viscosity, Amine ature, polses No.

170 270 331 200 300 3 230 280 351 250 150 280 06 365 170 180 200 160 320 DE'IA 230 110 318 BETA" 270 140 279 DE'IA TE'IA 170 260 (Equimolar). DETA TET 200 285 352 (Equimolar). v DETA 'IETA 230 210 355 (Equimolar). 4 DETA TET 250 150 352 (Equimolar).

1 Measured on a #5 spindle at 10 r.p.m. and 24 C.

2 An expression of the number of milligrams of K011 equivalent to the tltrable amine groups in a one gram sample.

3 Triethylenctetramine.

4 Diethylenetriamine.

At this temperature some of the unreacted polyamine as distilled out.

EXAMPLE III Table II outlines the physical properties of various reaction products of dimerized fatty acids and TEPA (tetraethylenepentamine) and their subsequent reaction with a commercially available epoxy resin. In each sample the reaction mixture contained one mole of TEPA per equivalent of acid. The reaction mixtures were held at the temperatures indicated for about 2 hours.

1 As determined by infrared analysis. 5 Measured on a #5 spindle at 10 r.p.m. and 21 0. 18 5A reaction product of bis-phenol A and epichlorohydrin having an epoxy equivalency pound per square inch (p.s.i.) and an ultimate fiexural strength of 13,000 p.s.i.

EXAMPLE 11 Three products were made from polymeric fat acids and (l) diethylene triamine (2) triethylene tetramine, and (3) an equimolar mixture of the two. In each case two moles of amine were heated with one mole of dimer acid to 170 for two hours. Then the temperature was lowered to 100, and the products were stripped of excess amine until 1.17 moles of amine per mole of dimer acid remained in each case. The viscosities of these products were measured at 24 C. Each product was then heated to successively higher temperatures for one to two hour periods, and after each heating period the viscosity was measured at 24 C. Table I shows 'how the viscosity was lowered after each period of heating above 200 except in those cases where there was a loss of amine (through distillation) as reflected in the amine number.

As shown in the examples one of the principal uses contemplated for the reaction mixtures of this invention is as a co-reactant with epoxy resins. There resins are complex polymeric reaction products of polyhydric phenols with polyfunctional halohydrius and/0r glycerol dichlorohydrin. The products thus obtained contain terminal epoxy groups. A large number of epoxy resins of this type are disclosed in Greenlee Patents 2,585,115 and 2,589,245. Several of these resins are readily available commercial products.

Typical polyhydric phenols useful in the preparation of epoxy resins include resorcinol and various bisphenols resulting from the condensation of phenol with aldehydes and ketones such as formaldehyde, acetaldehyde, acetone, methyl ethyl ketone and the like. A typical epoxy resin is the reaction product of epichlorohydrin and 2,2-bis(phydroxy phenyl)propane(Bisphenol A), the resin having the following theoretical structural formula,

where n is or an integer up to 10. Generally speaking, n will be no greater than 2 or 3 and is preferably 1 or less.

Epoxy resins may be characterized further by reference to their epoxy equivalent weight, the epoxy equivalent weight of pure epoxy resins being the mean molecular weight of the resin divided by the mean number of epoxy radicals per molecule, or in any case the number of grams of epoxy resin equivalent to one epoxy group or one gramequivalent of epoxide.

Many modifications and variations of the invention as hereinbefore set forth may be made without departing from the spirit and scope thereof, and therefore only such limitations should be imposed as are indicated in the appended claims.

Now, therefore, I claim:

=1. A cured composition containing an epoxy resin being a glycidyl polyether of a polyhydric phenol and having an epoxy equivalent weight of at least 100 and an aminopoly-imidazoline-amide which is the reaction product at temperatures in the range of 285 to 315 C. of (a) polymeric fat acids and (b) an excess of an aliphatic polyamine of the general structural formula amide has an acid number less than 5, an amine number 88 2867592 m the range of 270 to 500, a Brookfield viscosity of 100 to 1000 at 24 C., and contains at least 2 imidazoline groups for every amide group.

2. A cured composition containing an epoxy resin being a glycidyl polyether of a polyhydric phenol and having an epoxy equivalent weight of at least and an aminopoly-imidazoline-amide which is the reaction product at temperatures in the range of 285 to 315 C. for a period of about 2 hours of (a) polymeric fat acids and (b) an excess of an aliphatic polyamine of the general structural formula H(NHCR CR CR ),,NH where n is an integer of from 1 to 5 and R is selected from the group consisting of hydrogen and lower alkyl radicals containing less than 5 carbon atoms in which the ratio of reactants is at least 1.5 equivalents of amine for each equivalent of acid and said amino-poly-imidazoline-amide has an acid number less than 5, an amine number in the range of 270 to 500, a Broolctield viscosity of 100 to 1000 at 24 C., and contains at least 2 imidazoline groups for every amide group.

References Cited in the file of this patent UNITED STATES PATENTS 2,374,354 Kaplan Apr. 24, 1945 2,379,413 Bradley July 3, 1945 2,450,940 Cowan et a1. Oct. 12, 1948 2,705,223 Renfrew et a1. Mar. 29, 1955 2,723,241 De Groote et al Nov. 8, 1955' 2,839,549 Wilson June 17, 1958 Morris et a1. Ian. 6, 1959 

1. A CURED COMPOSITION CONTAINING AN EPOXY RESIN BEING A GLYCIDYL POLYETHER OF A POLYHYDRIC PHENOL AND HAVING AN EPOXY EQUIVALENT WEIGHT OF AT LEAST 100 AND AN AMINOPOLY-IMIDAZOLINE-AMIDE WHICH IS THE REACTION PRODUCT AT TEMPERATURES IN THE RANGE OF 285 TO 315*C. OF (A) POLYMERIC FAT ACIDS AND (B) AN EXCESS OF AN ALIPHATIC POLYAMINE OF THE GENERAL STRUCTURAL FORMULA 